STe service blog / CA300779-001 Rev 5.1

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Steve
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STe service blog / CA300779-001 Rev 5.1

Post by Steve » Thu Oct 14, 2021 2:34 pm

Hi guys,

Just doing some servicing on a customers STe, here is my work on it...

Board images here

* Clean disk drive
* Apply motherboard bus resistor fixes
* Replace a few important capacitors, like reset circuit
* Add STe ghosting fix capacitor
* Replace mouse/joystick port
* clean/resolder video port
* General machine clean
The beginning...
1. begin.jpg
1. begin.jpg (366.87 KiB) Viewed 547 times
What do we have missing here?
2. oops what is missing.jpg
2. oops what is missing.jpg (238.35 KiB) Viewed 547 times
Bit rusty on the shield
3. rusty shield.jpg
3. rusty shield.jpg (226.46 KiB) Viewed 547 times
Floppy needs a good clean and service!
4. dirty floppy.jpg
4. dirty floppy.jpg (435.48 KiB) Viewed 547 times
Time for a thorough clean
8. cleaning floppy.jpg
8. cleaning floppy.jpg (489.56 KiB) Viewed 547 times
9. clean floppy.jpg
9. clean floppy.jpg (375.47 KiB) Viewed 547 times
Let's replace the drive lube
5. old lube.jpg
5. old lube.jpg (436.33 KiB) Viewed 547 times
10. new lube.jpg
10. new lube.jpg (379.02 KiB) Viewed 547 times
Let's also re-cap the floppy
6. recap floppy 1.jpg
6. recap floppy 1.jpg (455.28 KiB) Viewed 547 times
7. recap floppy 2.jpg
7. recap floppy 2.jpg (430.39 KiB) Viewed 547 times
12. recap floppy motor.jpg
12. recap floppy motor.jpg (439.46 KiB) Viewed 547 times
Shame, after all that the floppy is still having issues!
11. floppy still bad.jpg
11. floppy still bad.jpg (235.64 KiB) Viewed 547 times
The floppy heads are physically touching/scratching the disk, you can see the black mark worn on the head. The floppy drive is TOAST. So we are going to go for a FlashFloppy instead!
13. chewing disks.jpg
13. chewing disks.jpg (280.69 KiB) Viewed 547 times

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Steve
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Re: STe service blog / CA300779-001 Rev 5.1

Post by Steve » Thu Oct 14, 2021 2:34 pm

Time to re-cap the PSU! It is a DSP-508a
18. psu before recap.jpg
18. psu before recap.jpg (300.89 KiB) Viewed 545 times
After the recap, looking good!
19. psu after recap.jpg
19. psu after recap.jpg (295.72 KiB) Viewed 545 times
Time to test the voltage output under load!
21. test 5v.jpg
21. test 5v.jpg (315.78 KiB) Viewed 545 times
20. test 12v.jpg
20. test 12v.jpg (320.8 KiB) Viewed 545 times

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Steve
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Re: STe service blog / CA300779-001 Rev 5.1

Post by Steve » Thu Oct 14, 2021 2:37 pm

Time to do some work on the motherboard, first the reset circuit and 470uf capacitor
15. re-cap reset circuit and 470uf.jpg
15. re-cap reset circuit and 470uf.jpg (483.28 KiB) Viewed 544 times
New 4700uf capacitor
PXL_20211014_183256157.jpg
PXL_20211014_183256157.jpg (552.79 KiB) Viewed 484 times
Now time to swap out the 10k SILs for 2.2k
16. old sils gone.jpg
16. old sils gone.jpg (479.69 KiB) Viewed 544 times
17. new sils in.jpg
17. new sils in.jpg (431.79 KiB) Viewed 544 times
Let's add the video ghosting fix while we're here
14. video ghosting fix.jpg
14. video ghosting fix.jpg (435.9 KiB) Viewed 544 times

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Steve
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Re: STe service blog / CA300779-001 Rev 5.1

Post by Steve » Thu Oct 14, 2021 2:37 pm

Time for some keyboard work
22. time to fix keyboard.jpg
22. time to fix keyboard.jpg (375.08 KiB) Viewed 537 times
Quite a bit of grunge to clean
23. a bit grungy.jpg
23. a bit grungy.jpg (270.43 KiB) Viewed 537 times
24. more grunge.jpg
24. more grunge.jpg (345.26 KiB) Viewed 537 times
Looks like the port area has a missing pad and broken trace
25. missing pcb pad trace.jpg
25. missing pcb pad trace.jpg (343.14 KiB) Viewed 537 times
28. new port soldered and trace patched.jpg
28. new port soldered and trace patched.jpg (399.44 KiB) Viewed 537 times
Guess who put it back together, all 30 or so screws, then realised he forgot to reflow the solder on the mouse port... Well, it's done now.
PXL_20211014_182220876.jpg
PXL_20211014_182220876.jpg (348.49 KiB) Viewed 487 times
30. new port.jpg
30. new port.jpg (329.93 KiB) Viewed 537 times
Let's give the keyboard and casing a good wash
26. time for a wash.jpg
26. time for a wash.jpg (393.77 KiB) Viewed 537 times
27. wash case.jpg
27. wash case.jpg (455.7 KiB) Viewed 537 times
Board nice and clean now
29. clean board.jpg
29. clean board.jpg (410.01 KiB) Viewed 537 times
Those rubber feet look melted! Let's replace them
31. old feet.jpg
31. old feet.jpg (224.84 KiB) Viewed 537 times
32. new feet.jpg
32. new feet.jpg (256.31 KiB) Viewed 537 times
After everything I've done so far does everything still work I wonder? Let's do a quick test :)
33. does it still work.jpg
33. does it still work.jpg (364.79 KiB) Viewed 537 times

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Steve
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Re: STe service blog / CA300779-001 Rev 5.1

Post by Steve » Thu Oct 14, 2021 2:40 pm

New HC type CPU

New Hotel drive
PXL_20211017_133852221.jpg
PXL_20211017_133852221.jpg (410.34 KiB) Viewed 417 times
PXL_20211017_133858595.jpg
PXL_20211017_133858595.jpg (411.36 KiB) Viewed 417 times

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PhilC
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Re: STe service blog / CA300779-001 Rev 5.1

Post by PhilC » Thu Oct 14, 2021 3:08 pm

@Steve what are you using for replacement feet?

repair looks good btw.
If it ain't broke, test it to Destruction.

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Steve
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Re: STe service blog / CA300779-001 Rev 5.1

Post by Steve » Thu Oct 14, 2021 3:15 pm

@PhilC Last time I ordered something from Centuriontech I added a bunch to my order, he stocks them.

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rubber_jonnie
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Re: STe service blog / CA300779-001 Rev 5.1

Post by rubber_jonnie » Thu Oct 14, 2021 3:23 pm

What's going on with that FDD? I've never seen one with all the motor coils exposed like that, looks like it's missing the rotor or something.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...

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Steve
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Re: STe service blog / CA300779-001 Rev 5.1

Post by Steve » Thu Oct 14, 2021 3:24 pm

rubber_jonnie wrote:
Thu Oct 14, 2021 3:23 pm
What's going on with that FDD? I've never seen one with all the motor coils exposed like that, looks like it's missing the rotor or something.
They're not normally exposed, I was just replacing the capacitor which needed the cover taking off.

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rubber_jonnie
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Re: STe service blog / CA300779-001 Rev 5.1

Post by rubber_jonnie » Thu Oct 14, 2021 3:34 pm

Steve wrote:
Thu Oct 14, 2021 3:24 pm
rubber_jonnie wrote:
Thu Oct 14, 2021 3:23 pm
What's going on with that FDD? I've never seen one with all the motor coils exposed like that, looks like it's missing the rotor or something.
They're not normally exposed, I was just replacing the capacitor which needed the cover taking off.
I get that, I'm used to seeing this:

IMG_20211014_152829.jpg
IMG_20211014_152829.jpg (237.03 KiB) Viewed 512 times

With the coils under the rotor (Silver disc) so that looks really strange to me. How is the spindle driven?

By cover did you mean the FDD case or the silver disk?

I'm just curious is all :)
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...

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